Placement of the reflexive pronoun in modal contexts

Question

The question is on the placement of nous, the reciprocal pronoun, in this passage from Camus's The Stranger.

Il disait qu’il s’était penché sur elle et qu’il n’avait rien trouvé, messieurs les Jurés. Il disait qu’à la vérité, je n’en avais point, d’âme, et que rien d’humain, et pas un des principes moraux qui gardent le cœur des hommes ne m’était accessible. « Sans doute, ajoutait-il, nous ne saurions le lui reprocher. Ce qu’il ne saurait acquérir, nous ne pouvons nous plaindre qu’il en manque.... »

QUESTION

1. Is that the only correct place for the reflexive pronoun while the following placement is wrong?

... nous ne nous pouvons plaindre...

2. Can I generalize the answer to the placement of reflexive pronouns in vouloir, devoir and savoir contexts?

Answer 1

I think what may be confusing you is the literary omission of "pas" in the sentence.

Would you understand it better if it had been written,

« ...nous ne pouvons pas nous plaindre qu’il en manque.... » ?

The reflexive pronoun will always follow the negated verb, so to answer your second question: yes, with all of those verbs the reflexive pronoun would come after. For example:

« ...nous ne devons (pas) nous plaindre qu’il en manque.... » ?

« ...nous ne voulons (pas) nous plaindre qu’il en manque.... » ?

The use of "savoir" in that sentence doesn't really make sense, but I think you get the picture anyway.

This is also all true for positive constructions, other pronouns, and reflexive verbs:

Vous n'aimez pas vraiment vous plaindre... / Vous aimez vraiment vous plaindre...

Tu ne devrais pas te laver les mains... / Tu devrais te laver les mains...

Il ne sait pas se coiffer. / Il sait se coiffer.

NOTE: It's much more common in speech to drop the ne and to keep the pas, even in these scenarios.

Answer 2

The sentence from Camus is right, meanwhile your example is generally wrong, although it might be used in poetry or literature.

The form "nous ne nous(...)" is correct in front of the reflexive verb only, like in "nous ne nous plaignons pas" (se plaindre is a reflexive verb). But once again, the form you used might be acceptable, but in literature or poetry only, and surely not in the current language.